Question

Solve 3x2 + 4x = −5.

Answer 1

Move the -5 over by adding 5 to both sides
3x^2+4x+5=0
must use quadratic formula

for an equation in the form
ax^2+bx+c=0
x=$\frac{-b+/- \sqrt{b^2-4ac} }{2a}$

a=3
b=4
c=5

x=$\frac{-4+/- \sqrt{4^2-4(3)(5)} }{2(3)}$
x=$\frac{-4+/- \sqrt{16-60} }{6}$
x=$\frac{-4+/- \sqrt{-44} }{6}$
x=$\frac{-4+/- 2\sqrt{-11} }{6}$
remember that√-1=i
x=$\frac{-4+/- 2i\sqrt{-11} }{6}$
x=$\frac{-2+/- i\sqrt{-11} }{3}$

x=$\frac{-2+ i\sqrt{-11} }{3}$ or x=$\frac{-2- i\sqrt{-11} }{3}$